Journal of cosmetic science最新文献

Twenty different brands of cosmetic products were purchased from supermarkets in Port Harcourt, Rivers State, Nigeria, with the aims to determine the levels of metals and assess the health risk to humans through long-term usage. The concentration of metals (arsenic, lead, mercury, cadmium, and nickel) in the cosmetic samples was measured with atomic absorption spectrophotometry after acid digestion. The concentration of metals in these brands of cosmetic studied ranged from As: 0.001-0.0161 mg/kg, Pb: 0.289-2.873 mg/kg, Hg: 0.001-0.0014 mg/kg, Cd: 0.001-0.334 mg/kg, and Ni: 0.007-2.748 mg/kg. The metal and metalloid contents were less than the regulatory limits set for both metal impurities and as color additives. The target hazard quotient, hazard index, and cancer risk were less than the acceptable limit, indicating a measure of safety. Cosmetics sold in Nigeria may not add to the body burden of metals and metalloids.

As the world is striving to become more sustainable, water consumption is considered an important area of focus, especially in those regions with limited freshwater resources. To address this issue, the personal care industry has identified faster rinsability of hair care products as a way to contribute to water preservation efforts. To understand rinsability, analysis of colloidal systems and an investigation into concentration of whole products in water is critical. However, particle size and particle migration in colloidal systems require the use of specialized optical methods. In previous research, we learned that conditioners form colloidal particles rather than true solutions during the rinsing process, and hence cannot be studied using ultraviolet-visible spectroscopy. Through this study, a Turbiscan instrument was determined to have the capability of measuring multiple light scattering given off by conditioner systems. Therefore, measurements of light scatter from a series of diluted conditioner dispersions can be used to generate a calibration curve to calculate unknown concentrations of conditioner in rinse water at different rinsing time intervals. The newly developed test method was successfully applied to determine the rinsability of various conditioner formulations on both virgin and bleached hair. The findings of our study will be presented here.

Research into biological manipulation of hair "quality" has ebbed and waned but today is in a resurgence. Hair appearance is regulated by multiple intervention opportunities-adding more hairs; increasing hair "amount" by modulating shaft diameter or shape; or, in principle, by altering shaft physical properties by changing its synthesis. It is likely that improved benefits may be achieved by combining multiple areas-minimizing follicle loss and miniaturization, maximizing shaft production, and treating the existing shaft. A previously overlooked opportunity is follicle metabolism: building "better" hairs. Hair production is energy intensive, and it is known that follicle metabolism influences shaft diameter. Multiphoton microscopy enables metabolic investigation of live, growing, human, hair follicles. This allows definition of multiple "zones" with vastly different metabolism: proliferation-where keratinocytes proliferate and migrate into specialized layers; production-proliferation ceases, and synthesis and patterning begin; construction and elongation-the structural framework is seeded and cells extend to create the nascent fiber; and maturation-gradual hardening and transformation into mature shaft. Recent investigations into the transition from construction to maturation reinforce this as a key developmental threshold, where shaft production transforms from a biologically driven into a biochemically driven process. We now name this "Orwin's transition."

A commercially-available instrument, previously intended to visualize and quantify hair shape and volume, has been modified to measure hair motion. Specifically, a transversal motor now induces a side-to-side oscillating tress stimulus, while a video camera records the outcome. Image analysis software allows for quantifying the amount of motion (i.e. the amplitude), the shape and volume of the hair during motion, and the homogeneity of the hair (i.e. bulk -vs- flyaways). Each of these parameters has considerable dependence on the frequency of oscillation and so evaluations are carried out by systematically varying this parameter. Preliminary validation experiments are documented which involved methodical variation of parameters that were presumed to be of importance. These included the size and shape of hair tresses, various hair treatments, and environmental conditions. As a result of the sizable amount of data that results, graphical depictions provide the best means of representation. For example, amplitude -vs- frequency plots describe the extent of hair motion as a function of energy supplied to the system. Visually noticeable decreases in tress motion were observed after applying small quantities of silicone oil to the hair. This occurrence reduced the measured amplitude of tress motion, while also moving the maximum amplitude to high frequency. Accordingly, it is supposed that improved motion is attained by inducing a higher amplitude at a given frequency, and/or by attaining comparable amplitude under the application of a lower frequency.

The goal of this work is to demonstrate the impact of UV and potential protective materials on hair fiber cuticle protein structure using Raman spectroscopy.

Hair fibers were examined by atomic force microscopy, nanoindentation. By indenting along (longitudinal) and across (transversal) the fiber, we evaluated the Young's modulus and its dependence on the moisture content (relative humidity) of the environment. The ratio of the two values collected for Young's modulus, at a given relative humidity, is defined as the anisotropy index (IA) of the fiber and the acquired results give the evolution of the index of anisotropy with the relative humidity. The use of the model of composite materials allowed us to relate the anisotropy index to the fiber internal architecture. The evaluation of the results acquired on the components of the fiber, within the frame of this model, ultimately points to a possible micro-structure of exocuticle, hindered under usual circumstances by its heavy cross-linking and only noticeable when the absorbed moisture swells the surrounding network and annuls, in this way, its effect.

Human hair, when bleached, undergoes oxidation of melamine granules and its structural proteins. This work aims to compare fragrance retention in both virgin and bleached hair, taking into consideration the interactions between fragrance compounds and hair before and after chemical modification. The bleaching process of straight dark brown Caucasian hair was carried out using a 4.5% wt. hydrogen peroxide solution at pH 9.5. Fragrance raw materials were incorporated in a shampoo formulation and applied on hair by washing, followed by rinsing. Hair was then let to dry under controlled conditions of temperature and humidity and the volatiles were collected by solid-phase microextraction and quantified by Gas Chromatography Mass Spectrometry (GC-MS). The more bleached the hair, the higher is the amount of sorbed substances during shampoo washing because of a higher number of holes in the hair structure, which increases its sorption capacity. Besides that, the impairments caused by oxidative reaction of hair surfaces are responsible for the faster evaporation of fragrant compounds and this behavior was compared with the loss of moisture of untreated and bleached hair.

To date, most single hair fiber mechanical testing publications in the literature have focused on tensile deformation with torsional measurements receiving far less attention. However, there is much to be gained from the measurement of torsional properties of a single hair fiber such as providing an insight into the shear stiffness changes that are associated with cuticle damage. This study outlines the potential use of torsional measurements to differentiate between cosmetic treatments where other modes of deformation do not. A core/shell modeling approach has also been applied to separate out the potential contributions of the cuticles and the cortex on the fiber torsional modulus and the effect of relative humidity on hair fiber structural components.